1. Field of the Invention
The present invention relates to a printed circuit board, and more particularly to an improvement in a terminal part of a printed circuit board.
2. Description of the Prior Art
FIG. 1 is a perspective view showing a conventional semiconductor device card such as an IC board used for a game card, and FIG. 2 is a perspective view showing a part of the semiconductor device card in which a shutter is opened. FIG. 3 is a perspective view showing an internal constitution of the semiconductor device board, and FIG. 4 is a sectional view taken along line IV--IV of FIG. 2.
Referring to FIGS. 1 to 4, a semiconductor device card 1 comprises a card like package 2 formed by a frame 3 and a pair of outer panels 4. A printed circuit board 5 is affixed to the frame 3 so as to be contained in the package 2. The printed circuit board 5 comprises a printed wiring board 6 (see FIG. 5) and a terminal board 7 (see FIG. 6) bonded o the front end of the printed wiring board 6. A number of electrode terminals 8 are provided on the terminal board 7, and each electrode terminal 8 is electrically connected to a printed wiring 9 on the printed wiring board 5 through a contact hole 10 which is formed in the terminal board 7 as shown in FIG. 4. Semiconductor elements 11 are mounted on both surfaces of the printed wiring board 6.
At ordinary times, the electrode terminals 8 are covered with a shutter 12 as shown in FIG 1. The shutter 12 is urged toward the front end of the printed circuit board 5 by means of a spring (not shown) which is installed between the shutter 12 and the frame 3. When the card 1 is inserted in a charging hole of a connector of a card reader (not shown), shutter receiving pins 13 provided in the charging hole touch bent-down projections 14 provided at both sides of the shutter 12 and push the shutter 12 toward the rear end of the card i against the tension of the spring. Thus the electrode terminals 8 are exposed to contact shoes of the connector, so that the semiconductor elements 11 in the card 1 are electrically connected with the external card reader.
By the way, in a case where the semiconductor elements 11 are mounted only on one surface of the printed wiring board 6, the electrode terminals 8 may be directly formed on the printed wiring board 6, as shown in FIG. 7. However, in a case where the semiconductor elements 11 are mounted on both surfaces of the printed wiring board 6 as shown in FIG. 4, it is necessary to locate the printed wiring board 6 at a central position in the thickness direction of the frame 3. Therefore the electrode terminals 8 are formed on the terminal board 7 and are electrically connected to the printed wiring board 6 through the through holes 10.
In the above conventional printed circuit board 5, the terminal board 7 is bonded to the printed board 6 by solder, for example, as shown in FIG. 8. In this case, the difference between the coefficients of thermal expansion of the boards 6 and 7 causes the terminal boards 7 to bend, whereby the flat arrangement of the electrode terminals 8 is impaired.